Research on the hard rock cutting characteristics of disc cutter under front-mounted water jet precutting kerf conditions

Abstract

To reveal the rock-breaking mechanism of the disc cutter under the front-mounted water jet precutting kerf conditions and study the effect of water jet kerf depth (H) and cutter spacing (S) on rock-breaking performance. The rock-cutting test and numerical simulations by disc cutter under the water jet precutting kerf conditions are conducted. The effects of H and S on the rock-crushing state, rock-cutting force, and rock-breaking efficiency are investigated, and the failure mechanism of internal rock cracks is revealed and discussed. The results show that with the increase of H, the disc cutter's vertical force and rolling force can be reduced by 48.2% and 32.9%, respectively, at maximum, but fail to improve the internal crack expansion capacity of the rock. The optimal combination of S of 80 mm and H of 9 mm can promote the expansion of the main crack and improve the rock-cutting efficiency. Meanwhile, the numerical simulations result further show that the microcrack initiation and propagation can describe the rock damage process. The rock internal crack initiation stage is accompanied by tensile and shear cracks, while the crack propagation stage is dominated by tensile cracks. Microscopic observation of the scanning electron microscope (SEM) reveals that the fracture mechanism for the major crack is tensile type.